干旱气象 ›› 2015, Vol. 33 ›› Issue (1): 98-109.DOI: 10.11755/j.issn.1006-7639(2015)-01-0098

• 论文 • 上一篇    下一篇

孤立云团造成的一次强对流天气分析

赵桂香, 王思慜, 邱贵强, 王晓丽   

  1. 山西省气象台,山西 太原 030006
  • 出版日期:2015-02-28 发布日期:2015-02-28
  • 作者简介:赵桂香(1965-),女,山西平遥人,硕士,正研级高工,主要从事天气气候分析与灾害性预报技术研究.E-mail:liyun0123@126.com
  • 基金资助:

    国家自然科学基金项目“黄河中游地区突发性大暴雨MCC结构特征研究”(41475050)和国家自然科学基金项目“回波合并在线性中尺度对流系统生成演变中的作用研究”(41275044)共同资助

Analysis of a Severe Convective Weather Caused by Isolated Cloud Cluster on 22 May 2013 in Shanxi Province

ZHAO GuixiangWANG SiminQIN GuiqiangWANG Xiaoli   

  1. Shanxi Meteorological Observatory,Tai Yuan 030006,China
  • Online:2015-02-28 Published:2015-02-28

摘要:

利用常规观测资料NCEP再分析资料卫星和雷达拼图产品等,结合WRF中尺度数值模拟,对2013年5月22日发生在山西省中南部的强对流天气进行了分析。结果表明:此次强对流天气过程中,河套地区正涡度平流的持续输送是500hPa切断涡旋形成、维持和发展的重要原因;低层冷平流沿其前方输入,后部有更强的暖平流输入,使涡旋不断加深发展,在其附近激发孤立对流云团,孤立云团上空存在高层辐散、低层辐合的垂直结构,使得其上空上升运动持续加强,孤立对流云团得以维持和发展,其间形成的r-中尺度和a-中尺度强对流云团是造成强对流天气的直接原因,而地面海上高压后部水汽的持续加强和高空脊前干空气南侵,产生明显干锋生作用,是强对流的重要触发机制。雷达组合反射率因子拼图显示,此次强对流过程是由单体回波发展合并加强造成的,这些单体回波的演变经历了“单体加强合并带状回波弓形回波减弱消亡”的过程;整个过程分为2个阶段,其回波面积、强度、移动速度不同,造成强对流天气特征差异明显。此次强对流天气存在3种类型,其温湿廓线结构及环境参数特征存在明显差异,可作为判断强对流天气类型的指标。

 

关键词: 区域强对流, 孤立云团, 干锋生、温湿廓线, 环境参数

Abstract:

Based on conventional observation data,NCEP reanalysis data,satellite images and radar mosaic products,and combined with WRF mesoscale simulation,the severe convective weather which occurred in the south of Shanxi on 22 May,2013 was analyzed. The results show that during this weather process,lasting transport of positive vorticity advection over Hetao area played a significant role in formation,maintenance and development of the cut - off vortex on 500 hPa level. Both the low - level cold advection from the front and more stronger warm advection from the back made the vortex develop continually,and excited isolated cloud clusters nearby. The vertical structure with high - level divergence and low - level convergence above the cloud clusters made the upward motion strengthen continuously. Consequently,the isolated cloud clusters maintained and developed. These meso - and meso - scale clusters were the direct cause leading to this severe convective weather. The dry frontogenesis caused by surface continuous strengthening of water vapor from the sea at the back of high pressure system and the invading of dry air at the front of ridge,was an important triggering mechanism of the strong convective weather. From the radar mosaic products of composite reflectivity,this process resulted from the development and merging of convective cells. The evolution of these cells went through a process from convective cell,merging,ribbon echo,bow echo to weakening and vanishing ,and the whole process was divided into two stages,when the area,intensity and moving speed of echoes were different,the characteristics of convective weather were different too. Obvious differences among three types during this process existed in temperature and humidity profiles and environmental parameters,which could be served as judging the severe convective weathers.

Key words: severe convective weather, isolated cloud cluster, dry frontogenesis, temperature and humidity profile, environmental parameter

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